Heat wave breaks record high for sixth day in row

Chicago continues setting record highs in late September 2017. The string of 90-degree-plus days that began Wednesday is the latest Chicago has ever seen temperatures above 90 degrees for five days in a row.

The temperature at O'Hare International Airport hit 91 at 1:10 p.m. and climbed to 92 later in the afternoon Monday, beating a record high temperature for a sixth day in a row as the late September heat wave marched on.

The previous record high for Sept. 25 was 90 degrees, set in 1933.

"This is the latest stretch of six consecutive 90-degree days on record in Chicago," the National Weather Service said in a statement. “There has never been a heat wave of this duration and magnitude this late in the season in Chicago."

It was also the sixth day in a row that temperatures got to 92 degrees. In the last 50 years, the only other times there were stretches of weather with temperatures at or above 92 degrees, it was in the middle of summer in 1988 and 2012, according to the weather service.

Sunday's high of 93 beat the old record of 91 set in 1891. Saturday’s high of 95 beat the previous record of 91 set in 1937. It also tied the hottest day of the year, the latest that's been done.

The heat wave is expected to last through Tuesday, with highs close to 90, with more normal temperatures returning Wednesday.

Monday was declared an air pollution action day, with the Illinois EPA declaring ozone levels or particulate-matter pollution levels were expected to be unhealthy for those sensitive to pollution levels and those with lung diseases.